A powered toothbrush is designed to assist a user by mechanically moving the head of the toothbrush. One approach in the art is to provide a vibratory element in the body of the toothbrush. U.S. Published Application No. 2002/0124333 relates to a mechanical vibratory device which causes the head part to vibrate. The vibratory device is accommodated in a front head part of the toothbrush, or in a neck-part region adjacent to the head part, said neck part connecting the head part to the handle, and is operatively connected to a power source, accommodated in the handle, via electrical connections running in the neck part, vibration-damping means preferably being provided in order to prevent vibration transmission to the handle, this achieves the situation where the vibrations which effect the improved cleaning action are produced predominantly in the head part and can only be felt to a slight extent in the handle, as a result of which comfortable handling of the toothbrush is achieved.
A number of approaches have been taken in the prior art to provide flexibility to the bristles during use of a toothbrush. U.S. Pat. No. 5,970,564, for example, discloses a toothbrush having an elastomeric ridge wherein there is a center array of bristles and there is a side array of bristles mounted in elastomeric boots. A number of patents disclose a toothbrush head having sets of bristles, each of which is mounted to a non-rigid or elastic support element. Examples of these approaches are found in U.S. Pat. Nos. 1,770,195, 2,244,098, 6,161,245 and 6,311,360 and in French Patent No. 38440.
The head of a conventional toothbrush usually has a flat or slightly altered surface to which cleaning elements are attached. Usually the cleaning elements are strands of plastic material(s) formed into tufts, bundles or other groupings. A goal of many toothbrushes is to accommodate the cleaning element profile to that of the teeth being cleaned. Achieving that goal is complicated by the difficulty in matching a toothbrush profile to the complex surface of a typical set of human teeth. The latter generally lie in a “C” shaped curve which presents the need for a brush to address a convex outer curve and a concave inner curve. In addition, the toothbrush should be capable of cleaning irregularities on the tooth surface as well as the interproximal area between teeth.
Blakeman U.S. Pat. No. 2,706,825 issued Apr. 26, 1955 discloses a replaceable bristle head for a toothbrush. The flexible head undulates in a manner so that rows of bristles move in a direction aligned with the axis of the toothbrush handle. U.S. Pat. Nos. 5,355,546, 5,483,722 and 5,839,149, all issued to Scheirer et al disclose cleaning elements mounted on a flexible membrane supported between a horseshoe shaped handle extension.
U.S. Pat. No. 5,651,158 issued Jul. 29, 1997 to Hans Halm discloses a toothbrush handle with a segmented head wherein adjoining segments are linked by an elastomeric material. The segments are primarily oriented transverse to the longitudinal axis of the toothbrush but may also be oriented parallel to that axis.
U.S. Pat. No. 6,088,870 discloses a latticework arrangement across the face of the toothbrush head. Tufts of cleaning elements are situated between the boundaries of the lattice and are mounted in the head so that each tuft flexes such that during brushing the bristle tufts will deflect in a manner that increases cleaning of the tooth surface.
U.S. Pat. No. 6,219,874 B1 issued Apr. 24, 2001 to Gelder, et al. discloses flexible mounting of toothbrush cleaning elements accomplished by segmenting portions of the toothbrush head, which segments are connected by flexible hinges.
U.S. Pat. No. 6,408,476 discloses another form of segmented toothbrush head with transverse grooves and an elastomeric portion joining the segments. A method of manufacturing this head is also disclosed.
It is well known that the ideal brushing technique from a dental hygiene perspective is an up and down stroke along the vertical surface of teeth which massages the gums while cleaning the teeth. However, due to a number of factors, including ergonomic difficulties, haste, lack of education or the like, few consumers use the recommended brushing technique. Rather, the typical consumer brushes across their teeth in a horizontal motion rather than a vertical movement. Various approaches have been taken by others to translate horizontal brush movement into partial vertical movement of the bristles or cleaning elements.
Translation of horizontal to vertical movement of cleaning elements is accomplished in U.S. Pat. No. 4,783,869 through use of a helix groove in a movable shaft within a toothbrush handle. The groove receives a pin which rides in the groove. This mechanism causes the toothbrush head to partially rotate or oscillate as the handle moves left-to-right or vice versa in the user's mouth. That rotation or oscillation causes the cleaning elements to move in a vertical plane perpendicular to movement of the toothbrush handle.
U.S. Pat. No. 5,481,775 discloses an arcuate shaped base for a toothbrush head aligned with the longitudinal axis of the head. A movable arcuate block containing cleaning elements is flexibly mounted on the toothbrush head. The block is free to slide on the head in a manner whereby the cleaning elements may travel in a vertical direction generally transverse to the typical side-to-side motion of the toothbrush.
U.S. Pat. No. 5,528,786 discloses pivotal mounting of cleaning elements that allows those elements to move up and down in concert with a side-to-side stroke along the teeth.
A general disclosure of flexible mounting for cleaning elements on a toothbrush head is contained in U.S. Pat. No. 5,839,149. In this patent the cleaning elements are mounted on a flexible membrane supported between a horseshoe shaped handle extension.
U.S. Pat. No. 6,141,817 discloses cleaning elements mounted on a flexible membrane that splay outward when the toothbrush is pressed against the user's teeth.
U.S. Pat. No. 6,338,176 B1 issued Jan. 15, 2002 to Smith, et al. discloses round sections of cleaning bristles mounted on individual pads that rotate within a toothbrush body. This converts backward and forward motion of the toothbrush into circular motion of the cleaning elements. The bristles associated with each pad are of varying height to accommodate irregularities, gaps, pockets and contours in natural tooth formation. The rotating cleaning elements can be supplemented with fixed cleaning elements adjacent thereto.
A toothbrush head should provide both proper support for the bristles, and be flexible enough during use to allow the bristles to conform to the shape of a user's mouth or teeth. Additionally, construction techniques should be inexpensive, versatile and consistent.
In an attempt to meet these criteria, a process known as “Anchor Free Tufting” (“AFT”) has been used in the formation of toothbrush heads. In such an AFT process, a head plate for holding toothbrush bristles, and for eventual insertion into a toothbrush body, is typically formed of a rigid plastic that is conducive to sonic welding. The head plate is formed with a solid perimeter and defines a field of variously shaped and sized holes within this perimeter. Fibers that are to form the tufts are then placed in the holes in the field of the head plate, and the backs of the tufts are melted together to fix their position relative to one another.
The tufted head plate is then inserted into a predefined receiving portion of the head portion of a toothbrush handle and is sonically welded into place. The brush is then end-rounded and packaged for sale as a traditional toothbrush.
However, this manufacturing process results in a toothbrush with a very rigid head that does not easily conform to the physical characteristics of a user when brushing. Therefore, it would be desirable to provide a toothbrush that can be conveniently manufactured by the above process, but provides the desired flexibility of the head of the toothbrush during use.
It would also be desirable if a toothbrush could be provided having various cleaning elements on a head, such as bristles with different degrees of flexible mounting, to have a enhanced cleaning effect when moved by a mechanical vibratory element.